Endoscopic surgery in the abdominal cavity of an animal, such as, for example, a human, may include insufflating the abdomen to create a space in which surgeons may introduce endoscopic surgical instruments. Access to the abdomen may be created with a trocar assembly, which may include a hollow cannula and a solid shaft passing through the cannula. The solid shaft may include a sharp tip that pierces the abdominal wall to form an otomy and that guides the cannula partially into the insufflated abdominal cavity. After the cannula is in place in the otomy, the solid shaft may be withdrawn from the cannula, leaving a passage through the cannula that the surgeon may use to access the abdominal cavity using endoscopic surgical devices. The cannula may include a seal, such as a duck bill seal, at its distal end that is biased in a closed position to prevent or retard the escape of gases insufflating the abdomen. A surgeon chooses a trocar size that closely fits the endoscopic tools he intends to introduce therethrough. For example, if the endoscopic tool to be used has a diameter of 14 millimeters, then a cannula having an inner diameter of slightly more than 14 millimeters would be used. The endoscopic tool passes through the cannula and opens the seal on the cannula. The close sizing between the endoscopic tool and the cannula prevents or retards the escape of the gasses insufflating the abdomen that would otherwise pass through the open seal.
Magnetic anchoring and guidance systems (MAGS) have been developed for use in minimally invasive procedures. MAGS include an internal device attached in some manner to a surgical instrument, laparoscope or other camera or viewing device, and an external hand held device or external control unit (“ECU”) for controlling the movement of the internal device. Each of the external and internal devices has magnets which are magnetically coupled to each other across, for example, a patient's abdominal wall. In the current systems, the external magnet may be adjusted by varying the height of the external magnet.
The camera is attached to one or more tethers that provide power to the camera's electronics, image date, and, optionally, water or gases. The tethers lead out through the cannula and pass through the seal on the cannula. The presence of the tether prevents the seal on currently-available cannulas from closing, thereby creating a leak that enables the insufflation gases to escape when other endoscopic surgical instruments are not placed in the cannula.
The foregoing discussion is intended only to illustrate various aspects of the related art in the field of the invention at the time, and should not be taken as a disavowal of claim scope.